Removal and installation, checking of the intake air temperature sensor. Models 320i, 325i, 328i (BMW 3 Series E36)

The temperature sensor measures the temperature of the intake air and transmits this information to the control unit. Together with the signal from the air flow meter and the heating element, this information is used to determine the mass of the incoming air. Like the coolant temperature sensor, the air temperature sensor contains an NTC element (NTC = negative temperature coefficient), the resistance of which decreases with increasing temperature. If the sensor fails, the control unit will experience uneven engine operation at low outside temperatures and a cold engine or at extremely high temperatures.

Checking the temperature sensor

Disconnect connector "1" of the throttle switch,

Disconnect connector "2" of the air temperature sensor and connect an ohmmeter to the sensor contacts.

Measure the resistance and compare it with the specified value. Depending on the ambient temperature, intermediate values are possible. For specified values, see the table below.

If there are any deviations from the specified values, remove the sensor.

Place the sensor on a wire hook in a water bath so that it does not touch the walls of the vessel. Cool the water with ice cubes, and then warm it up on a hotplate. At the specified temperatures, remove the sensor and measure the resistance between its contacts.



If the temperature sensor is normal, connect the voltmeter to the connector contacts and ground.

Turn on the ignition. The specified value is about 5 volts. If there is no voltage, ring the wire.

Ring the ground wire.

If the wire sensors are normal, the control unit is defective.

Removal

Remove the air filter together with the air intake hose.

Unscrew the temperature sensor.

Installation

Screw in the temperature sensor with a new gasket and tighten to a torque of 12-14 Nm.

Caution: Do not overtighten the temperature sensor.

Connect the throttle switch and temperature sensor connectors. Snap the wire clips into place.

Install the air filter together with the air intake hose.